This invention relates to waveguide cavity filters for use in radio communications systems and, in particular, to waveguide cavity filters disposed in a triplet configuration for implementing a bandpass filter.
As demonstrated by the high prices paid for licenses to portions of the radio frequency spectrum in the United States, there is a need to maximize the services that can be provided over a limited bandwidth. This need is particularly critical in the field of cellular phone communication systems.
Waveguides may be employed in communication systems to minimize losses for high frequency radio waves. Conventionaly, waveguide bandpass filters include one or more resonance cavities and coupling probes disposed between each cavity. The use of probes is disadvantageous because the placement of probes is often unpredictable, unrepeatable, and costly. Accordingly, highly efficient waveguide bandpass filters that minimize or eliminate the use of probes have been difficult to achieve.